Solutions

Speed-related problems are often the result of improper crimper selection or improper adjustment. Here are just a couple examples of the many ways Lako Tool can provide you with accurate, reliable packaging solutions.

We've included details of each example, along with some other helpful suggestions.

Potential Problem (1)

Problem:  Improper Crimper Selection
Unable to increase the speed (number of packets per minute) past a certain point, regardless of temperature setting. crimpers have vertical serrations (grooves at right angles to knife slot).

Solution:

Switching from a vertical to a horizontal serration ("gear tooth"-grooves parallel to knife slot) can make a surprising difference in your machine's run speed.

The chart below clearly indicates there is a substantial advantage in switching to crimpers with suitable horizontal serrations. As the chart shows, both the maximum speed and the allowable operating range are significantly higher with horizontal serrations.

The right ends of the color graph bars are the points at which increased speed produced a weak seal, and the left ends of the color bars represent the low speed at which seal distortion (due to overheating) became apparent:

Potential Problem (2)

Problem: Improper Adjustment
On the same crimper pair, the lead seal is strong, but the trailing seal-on the opposite side of the knife-is weak. This condition gets worse as the speed is increased.

Solution:
This is usually caused by the knife sticking too far out of the crimper. As the crimpers rotate into mesh, the first side seals. As the knife contacts the anvil, the misadjusted knife pushes the crimpers too far apart.

As the second seal on the crimper rotates into position, it doesn't seal. This is because the top crimper is still up in the air, and can not come back down against the film fast enough during high speed rotation.

The knife may have been adjusted out too far for several reasons:

1. The knife is dull. Replace both the knife and the anvil.
2. You're using the wrong type of knife. On some hard-to-cut heavy structure films, the included angle on the cutting edge of the knife needs to be less.
3. The spring tension is too weak. (be careful not to adjust too tight!)
4. In some situations, at high speed, the spring mechanism is not capable of bringing the head back down in time (like a floating hydraulic valve lifter).

Some Helpful Suggestions:

Change your anvils regularly:
When changing a dull knife, you should also change the anvil at the same time. Running a new knife against a used anvil severely shortens the life of the knife: the worn surface of the anvil quickly dulls the sharp edge.

Proper care:
Your knives, crimpers, and punches will last far longer if you use a brass brush instead of a steel wire brush to clean them.

Make sure your gear-teeth are in good condition:
One item often overlooked on crimper shafts is the condition and adjustment of the phasing and backlash shaft gears. For maximum seal integrity, the gear teeth need to be in like-new condition; ideally, just as precise as we make the sealing form on the crimpers. This is especially important on horizontal (gear tooth) seal forms, where the grooves on the sealing surface of the crimpers are parallel to the knife slot.

Check your washers:
Are you using hardened (or unused) washers between the mounting screws and crimpers? If not, the crimper will likely move out of position as you tighten the screws, causing misalignment of the crimpers and unsatisfactory seals.